Live Measurement of Stress Distribution in Loaded Adhesive Bonds

摘要

The SKZ,Germany's largest plastics institute,and the Fraunhofer Institute for Integrated Circuits(IIS)have recently begun work on a joint project to identify the stress distribution in flexible bonded joints.The objective of the project is to develop further an innovative multi-dimensional in-situ measurement system which will enable the deformation of adhesive layers under load to be described more accurately.Bonding is becoming an increasingly popular joining method.Bonded joints are light in weight and ideal for combining different types of materials and linking together thin components,which makes them particularly suitable for use in lightweight structures.However,it is not possible to determine the quality of bonded joints solely on the basis of the properties of the individual materials,because it is largely dependent on the interaction of all the materials used and on the resulting multi-layer adhesive bond.A widely used method of measuring the quality of bonds is the tensile shear test.However,the results of the test are based on highly simplified assumptions about the stress distribution in the adhesive.They also depend on the shape of the component and ignore the multi-layer structure that forms in every bond when it is placed under load.